Currently my greatest fear is that Grodziskie/Grätzer is going to get classified as a sour beer, when there's not a shred of evidence that it ever was. Type "Grätzer" and "sour" into Google and see how many hits you get.
This is the commercial description of Dr. Fritz Briem's Lichtenhainer, sorry, Grätzer:
"Grodziskie or Grätzer is a Sour Smoked Wheat Ale that was brewed in the 1900s in East Prussia and dates back to as early as the 15th century. It was named after the Polish town of Grodzisk Wielkopolski or Grätz in German. Our historic version is brewed according to the German Purity Law with air-dried barley malt and beech smoked wheat malt and hopped with Perle and Saaz. A sour mash is created using the old and forgotten technique called “Digerieren.” Finally a three month aging and maturation process creates a complex sour, smoky and heavily hopped wheat ale."That's an almost Dornbusch level of mistakes.
1. Grodziskie/Grätzer wasn't sour.
2. It isn't a fucking Ale.
3. Grodzisk is not East Prussia. When German, it was in the region of Posen. Grodzisk is approximately 300 km from the closest point in East Prussia.
4. Grodziskie/Grätzer was 100% wheat malt.
5. Grodziskie/Grätzer was 100% wheat malt smoked over oak not beech.
6. The Reinheitsgebot was in force in Posen from 1906* until Polish independence in 1919.
"The beer is not without controversy, however. Do a bit of googling and you’ll soon discover incredibly heated debates about the style. “Is it a sour beer? How much oak-smoked wheat should be used? What sort of yeast should you ferment with?” BrewLab was intrigued, and so was the rest of the SF beer community."
San Francisco Brewers' Guild Blog.
There has been no controversy over whether Grodziskie/Grätzer is sour. Just some people who've ignored (or not bothered to look for) the historical and guessed it was a sour beer. That's not a controversy, just poor scholarship.